von Kalm L, Crossgrove K, Von Seggern D, Guild G M, Beckendorf S K
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
EMBO J. 1994 Aug 1;13(15):3505-16. doi: 10.1002/j.1460-2075.1994.tb06657.x.
In Drosophila, all of the major metamorphic transitions are regulated by changes in the titer of the steroid hormone ecdysone. Here we examine how a key regulator of metamorphosis and primary ecdysone response gene, the Broad-Complex, transmits the hormonal signal to one of its targets, the Sgs-4 glue gene. We show that Broad-Complex RNAs accumulate in mid third instar larval salivary glands prior to Sgs-4 induction, as expected for the products of a gene that regulates the timing of Sgs-4 activation. The Broad-Complex codes for a family of zinc finger transcriptional regulators. We have identified a number of binding sites for these proteins in sequences known to regulate the timing of Sgs-4 induction, and have used these sites to derive a binding consensus for each protein. Some of these binding sites are required in vivo for Sgs-4 activity. In addition, rbp+, a genetically defined Broad-Complex function that is required for Sgs-4 induction, acts through these Broad-Complex binding sites. Thus, the Broad-Complex directly mediates a temporal and tissue-specific response to ecdysone as larvae become committed to metamorphosis.
在果蝇中，所有主要的变态转变都受类固醇激素蜕皮激素滴度变化的调节。在此，我们研究变态的关键调节因子和初级蜕皮激素反应基因——宽泛复合体（Broad-Complex）是如何将激素信号传递给其靶标之一——Sgs-4胶水基因的。我们发现，如调控Sgs-4激活时间的基因产物所预期的那样，宽泛复合体RNA在Sgs-4诱导之前的三龄幼虫中期唾液腺中积累。宽泛复合体编码一个锌指转录调节因子家族。我们在已知调控Sgs-4诱导时间的序列中鉴定出了这些蛋白质的多个结合位点，并利用这些位点推导出了每种蛋白质的结合共有序列。其中一些结合位点在体内对Sgs-4活性是必需的。此外，rbp+是Sgs-4诱导所需的一个由遗传学定义的宽泛复合体功能，它通过这些宽泛复合体结合位点发挥作用。因此，当幼虫进入变态阶段时，宽泛复合体直接介导了对蜕皮激素的时间和组织特异性反应。
